Phelps and Tillotson, Jr. — Cyanacetic Acid. 265 



This acid, when neutralized with ammonium hydroxide, gave 

 no precipitate with lead nitrate, indicating that no malonic or 

 glycollic acid was present, and on analysis proved to be pure. 



I. 0-4000 grm. gave 59*5 cm3 moist nitrogen at 25° and 756*8 mm . 

 N = 16 '51 per cent. 

 II. 0-2910 grm. gave 43 -l cm3 moist nitrogen at 25° and 762-l mm . 

 N = 16-57 per cent. 



Required for C 3 H 3 2 N, N = 16-48 per cent. 



The alcohol was made as anhydrous as possible by repeated 

 distillations over calcium oxide. For experiments (2) to (5) 

 inclusive, absolute alcohol obtained as described above was 

 charged with dry hydrochloric acid gas in the proportions of 

 ten grams of hydrochloric acid per liter of alcohol. Pure zinc 

 chloride of commerce, freshly fused, and sulphuric acid, sp. 

 gr. 1*84, were used also as catalyzers. 



In all of the experiments recorded in the table, fifty grams 

 of cyanacetic acid with 40 cm3 of alcohol, alone or charged with 

 hydrochloric acid in the proportions already given, together 

 with a definite weight of zinc chloride or sulphuric acid, 

 were heated to a temperature of 100°-110°, using the special 

 arrangement of flasks for esterification and the procedure for 

 recovery of the pure ester, described in a former paper.* 



The error inherent in the process was determined by treat- 

 ing 70 grm. of pure cyanacetic ester with 4 grm. of sulphuric 

 acid and alcohol in the esterification apparatus, under the 

 same conditions as in the several experiments, and recovering 

 in the same manner. Under these conditions 68*33 grm. were 

 recovered. Thus the results shown in the table must be 

 approximately 2*5 per cent lower than the amounts of cyan- 

 acetic ester actually formed. 



From experiment (l) it appears that with absolute alcohol, 

 using no catalyzer, 63-5 per cent of cyanacetic ester may be 

 obtained, but if the alcohol be charged with 1-25 per cent of 

 hydrochloric acid, as in experiment (2), the yield is increased 

 25 per cent. In experiment (3) the addition of one gram of 

 zinc chloride raises the yield one per cent over that of experi- 

 ment (2) where no zinc chloride was used, and the presence 

 of 10 grm. of zinc chloride further increases the yield to 95*1 

 per cent of cyanacetic ester actually obtained. In all the experi- 

 ments in which alcohol charged with hydrochloric acid was 

 used, a small amount of ammonium chloride, possibly 0'1 grm., 

 separated during the treatment at 100°-110°, showing partial 

 conversion to malonic ester. In experiment (5) no ammonium 

 chloride was observed when the esterification was performed 

 at 85°-90°, but under these conditions the yield of cyanacetic 



* This Journal, xxiv, 194. 



Am. Jour. Sci. — Fourth Series, Vol. XXVI, No. 153. — September, 1908. 

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